1. Field of the Invention
This invention relates to a packaging machine for producing reclosable packages, and more particularly, to a sealing station and a welding station for installing resealable closures or zippers onto packages produced on a form-fill-and-seal (FFS) packaging machine. The invention further relates to retrofitting horizontal FFS packaging machines to incorporate the zipper installing function.
2. Background Information
The formation of packages on form-fill-and-seal machines takes many forms. There is a spectrum of form-fill-and-seal packaging machines which extends from horizontal and vertical bag-forming machines which form packages from a single web of packaging material to rollstock machines which form packages by sealing an upper web to a formable lower web. Such machines package an unending array of consumable goods, including food products, non-food products, and medical products.
While the sealing and channel-forming die assembly of this invention may be broadly applicable to packaging machines, the information herein is presented in the milieu of a horizontal, rollstock form-fill-and-seal machine, especially those which provide for packaging of products in a vacuum or a modified atmosphere. These machines make thermoformed packs which are most commonly used for foods, such as sliced meats and cheeses. A further consideration here is seal integrity and this becomes critical as such products most often require vacuum or modified atmosphere packing.
In recent years many thermoformed packages are popularly supplied with primary and secondary closures, one of which is resealable. The resealable closures, commonly known as sealable profiles or zippers, have been marketed under such trademarks as Fresh-Loc and Zip-Pac. While the resealable closure has wide consumer acceptance, the requisite machine adaptation to the rather bulky closure (as compared to film) has been problematic. Typically because of their geometry and other inherent problems, the incorporation of resealable closures into a package frequently creates wrinkles in one packaging film or the other resulting in incompletely sealed packages. These incompletely sealed packages or leakers, in which a loss of seal integrity is experienced, are frequently not detectable by the quality control of the packager, but become apparent later in the distribution channel. When packaged goods without seal integrity get to the marketplace or into the consumer's hands, such goods have a reduced shelf life or experience spoilage.
In the past, horizontal FFS machines installed zippers at a separate working station between the forming station and the evacuation and sealing station. The zipper installing work station had a dedicated lifting device associated therewith. The zippers provided in the form of spooled zipper blanks, when exposed to the high temperatures of the zipper installation stations, tended to twist out of alignment becoming difficult to manage and frequently causing the wrinkling of the packaging film described hereinabove.
The following patents are known to the inventors and are presented for the further discussion of the prior art:
Inventor (Assignee)Issue DatePatent Application20020015537Strand et. al. (Sargento)Feb. 7, 2002Patent6,185,907Malin et al. (ITW)Feb. 13, 20016,138,439McMahon et al. (ITW)Oct. 31, 20006,138,436Malin et al. (ITW)Oct. 31, 20006,044,621Malin et al. (ITW)Apr. 04, 20005,941,643Linkiewicz (Triangle Pkg)Aug. 24, 19995,930,877Thorpe et al. (ITW)Aug. 03, 19995,832,570Thorpe et al. (ITW)Nov. 10, 19985,747,126Van Erden et al. (ITW)May 05, 19985,551,208Van Erden (ITW)Sep. 03, 19965,425,216Ausnit (ITW)Jun. 20, 19955,412,924Ausnit (ITW)May 09, 19955,198,055Wirth et al. (Alcoa)Mar. 30, 19935,118,203Andronico (J.W. Kutter, Inc.Jun. 2, 19925,105,603Natterer (Multivac)Apr. 21, 19924,876,842Ausnit (ITW)Oct. 31, 19894,782,951Griesbach et al. (Oscar Mayer)Nov. 08, 19884,589,145Van Erden et al. (ITW)May 13, 19864,296,588Vetter (Multivac)Oct. 27, 19814,240,241Sanborn (W.R. Grace & Co.)Dec. 23, 1980RE. 28,969Kakuji NaitoSep. 21, 19763,038,225S. Ausnit (ITW)Jun. 12, 1962
The development of technology in the consumer goods and food packaging area is driven by three distinct technologic/economic forces, namely, (1) manufacturers of goods/food producers requirements; (2) packaging film/zipper blank innovation; and, (3) packaging machine development. In the first category, the patent application assigned to Sargento Foods, Inc., U.S. Patent Application 20020015537; and the patent assigned to Oscar Mayer Foods Corporation, U.S. Pat. No. 4,782,951 are primary examples. In the packaging film innovation area, the patents assigned to Reynolds Consumer Products, U.S. Pat. No. 5,198,055 and to W. R. Grace & Co., Cryovac Division, U.S. Pat. Nos. 4,240,241 and 4,437,293 are discussed.
In the following, it is seen that the prior art packaging machine patents arise from two main streams of technological development, namely, the Illinois Tool Works, Inc., Glenview, Ill. products and the Multivac Sepp Haggenmuller KG, Wolfertschwenden, West Germany, (Multivac) products. The Illinois Tool Works line includes the Minigrip, Inc. technology, which corporation is now part of Illinois Tool Works, Inc. It is noted that the reclosable seal patents to Griesbach et al. of Oscar Mayer Foods Corporation and Wirth et al. of Reynolds Consumer Products, Inc., are related to the Multivac technology.
U.S. Patent Application 20020015537—Strand et al. (Sargento Foods, Inc.)—Feb. 7, 2002
This application describes a resealable bag for a food product which is manufactured by an HFFS packaging machine such as described in Sanborn, U.S. Pat. No. 4,240,241 (W.R. Grace & Co.) and also has a tamper-evident seal.
U.S. Pat. No. 6,138,439—McMahon et al. (ITW)—Oct. 31, 2000
The patent describes an HFFS packaging machine which mounts a zipper to film extensions of an already sealed package at a zipper and slider insertion and attaching station dedicated. After installation of the zipper, a slider is separately inserted into the assemblage.
U.S. Pat. No. 5,198,055—Wirth et al.—Mar. 30, 1993
Wirth et al. discloses a method of forming a reclosable package using special profile strips (zipper components), the strips and a resulting package. The profile strips have a flange element which includes, by being a thickened element or by adding a buffer strip thereto, a thermal barrier. The barrier is designed to prevent the flanges from fusing together during the installation step of flange-film sealing.
U.S. Pat. No. 5,118,203—Andronico, D. (T.W. Kutter, Inc.)
The apparatus of this invention is an HVFFS Tiromat 3000 manufactured by Kramer & Grebe (Canada) Ltd., Waterloo, Ontario, which employs a zipper application assembly prior to the forming, filling and sealing functions.
U.S. Pat. No. 5,105,603—Natterer, J. (Multivac)—Issued Apr. 21, 1992
The patent to Natterer describes a rollstock HVF-F-S packaging machine having a work station dedicated to applying the closure strip to the lower formable web prior to entering the sealing and evacuation where the package is mated with the lidstock, evacuated and sealed. The work station for applying the closure strip is not temperature controlled.
U.S. Pat. No. 4,782,951—Griesbach et al.—Nov. 8, 1988
The patent to Griesbach et al. discloses a resealable package having interlocking closure strips outside of a hermetic seal. The seal is of a peelaway type so as not to destroy the integrity of the package upon opening of the package.
Griesbach et al. discloses a reclosable package comprising interlocking closure strips positioned outside of a hermetic seal or seal area and the method for producing same. The hermetic seal is of the easy-open or peelaway type so as to not destroy the integrity of the package or closure strips upon opening of the package.
U.S. Pat. No. 4,296,588—Vetter (Multivac)
This patent discloses a sealing station for a HVFSS which provides a deflector to divert the air and moisture removed from the product-containing receptacle and thereby improve the vacuum achieved during the evacuation cycle.
U.S. Pat. No. 4,240,241—Sanborn, P. A. (W.R. Grace & Co.) —Dec. 23, 1980
The patent describes a thermoform machine for packaging a product in a reclosable package in a straight through process on a single machine rather than making a reclosable pouch on one machine and performing the filling, evacuating and sealing process on another machine.
U.S. Pat. RE: 28,969—K. Naito—Sep. 21, 1976
The patent discloses a reclosable plastic bag having interlocking rib and groove elements integral with the plastic of the bag with the elements being designed so that the bag opens easily from the outside, but resists opening from the inside.
U.S. Pat. No. 4,876,842—Ausnit—Oct. 31, 1989
A method of and apparatus for packaging product masses in a form, fill and seal machine, wherein a continuous length of packaging film is joined in running relation by a continuous length of separately formed plastic reclosable fastener assembly having interlock profile strips spot sealed together at package length intervals. The corunning fastener strip assembly and the packaging film are oriented so that the spot seals of the strip are located in alignment with the spaces between the product masses on the film to assure that the fastener strip assembly will be cross sealed at the spot seals when the film is cross sealed between the product masses to provide individual packages. The orienting may be effected by an indexing arrangement including sensor response to index marks on the film and the fastener assembly.
In reviewing the prior art as described hereinabove, the zipper installation procedures are not conducted at the sealing station simultaneously with the sealing and/or evacuation functions. Present zipper installation procedures frequently interfere with package integrity. It is not taught how to sufficiently isolated the zipper installation from the sealing function so as to avoid the introduction of air into product receptacles, thereby reducing product shelf life and the overall quality of the packaged goods. Unlike what is known to date, in the disclosure which follows, it is taught how the sealing and evacuation function, is combined at the work station with zipper blank feeding and tacking function. Moreover, the teaching includes how to stabilize the zipper blank during processing by controlling the temperature conditions under which installation takes place. The submission of the above list of documents is not intended as an admission that any such document constitutes prior art against the claims of the present application. Applicant does not waive any right to take any action that would be appropriate to antedate or otherwise remove any listed document as a competent reference against the claims of the present application.